Multipart form-data body builder

CLAUDE.md

@@ -97,6 +97,7 @@ go-sdk/
 ├── serde/                     # Marshaler/Unmarshaler seam + JSON default + Tristate
 ├── sse/                       # Server-Sent Events (WHATWG) parser
 ├── webhook/                   # inbound signature verification (HMAC + timestamp)
+├── formdata/                  # multipart/form-data body builder
 ├── .golangci.yml  Makefile  .github/workflows/ci.yml
 └── CONTRIBUTING.md  CLAUDE.md  README.md  LICENSE
 ```

README.md

@@ -62,6 +62,7 @@ standard library.
 | [`serde`](./serde) | Serialization seam (Marshaler/Unmarshaler) with a JSON default, plus Tristate for PATCH payloads. |
 | [`sse`](./sse) | Server-Sent Events (text/event-stream) WHATWG parser. |
 | [`webhook`](./webhook) | Inbound webhook signature verification (constant-time HMAC + timestamp tolerance). |
+| [`formdata`](./formdata) | Multipart/form-data request body builder (replayable; file uploads). |
 | root [`dexpace`](.) | Umbrella `Client` wiring the default policy stack. |
 
 ### Pipeline order

doc.go

@@ -62,5 +62,8 @@
 // The webhook package verifies inbound webhook signatures (constant-time HMAC
 // with a timestamp-tolerance window).
 //
+// The formdata package builds replayable multipart/form-data request bodies for
+// file uploads.
+//
 // All of core depends only on the Go standard library.
 package dexpace